Obesity is currently one of the major health problems, especially in the industrialised countries, with serious consequences in cardiocirculatory and skeletal terms.
Carbohydrates are an important source of calories, and contribute to the synthesis of fats in individuals predisposed to obesity or type II diabetes. As hyperglycaemia leads to an increase in energy deposits, the availability of substances that reduce bioavailable glucose is very important. As starches are the main source of glucose, specific α-glucosidase and α-amylase inhibitors, obtained from plant materials or by synthesis, have been studied. It has long been known that some seeds and pulses contain substances which can have adverse effects on the diet if eaten before they are completely cooked. Many pulses contain protease inhibitors, amylase inhibitors and substances that discourage predators from continuing to use them by reducing the appetite. These substances, called phytohaemagglutinins, can cause hyperplasia of the pancreas at high doses, but can be useful in appetite control at lower doses.
At high doses, these lectins survive the intestinal transit and bond to the enterocytes where they cause the secretion of cholecystokinin, a trophic hormone that stimulates secretion by the pancreas, consequently causing its enlargement. Cholecystokinin also has favourable effects, because it reduces the appetite by reducing gastric motility.
As excess blood glucose leads to an increase in energy deposits, substances that reduce the availability of free glucose after an intake of starchy carbohydrates in the diet are very important. Most glucose originates from the breakdown of starch, which begins in the mouth due to the effect of ptyalin; this enzyme detaches saccharide chains, which in turn are converted to glucose by saccharases and α-glucosidases. α-amylase, secreted by the pancreas in the duodenum, demolishes the starch in glucose chains in the intestine, where it is converted to glucose due to the effect of α-glucosidase.
It is therefore obvious that in order to achieve a substantial reduction in the release of glucose, it is important to have both α-amylase inhibitors and α-glucosidase inhibitors.
The α-amylase inhibitor in itself considerably reduces the quantity of glucose originating from the starches present in the diet, and reduces the appetite after repeated administration.
It has now surprisingly been found that by combining Phaseolus vulgaris extracts with Salacia oblonga extracts in the ratio of between 1:1 and 1:4, a marked reduction in blood glucose is obtained in humans. It is also known that a reduced food intake leads in any event to a reduction in the accumulation of fatty deposits.